Method and apparatus for measuring temperature

ABSTRACT

Apparatuses and methods for measuring substrate temperature are provided. In one or more embodiments, an apparatus for estimating a temperature is provided and includes a plurality of electromagnetic radiation sources positioned to emit electromagnetic radiation toward a reflection plane, and a plurality of electromagnetic radiation detectors. Each electromagnetic radiation detector is positioned to sample the electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources. The apparatus also includes a pyrometer positioned to receive electromagnetic radiation emitted by plurality of electromagnetic radiation sources and reflected from a substrate disposed at a reflection plane and electromagnetic radiation emitted by the substrate. The apparatus includes a processor configured to estimate a temperature of the substrate based on the electromagnetic radiation emitted by the substrate. Methods of estimating temperature are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit to U.S. Appl. No. 62/689,994, filed onJun. 26, 2018, which is herein incorporated by reference.

BACKGROUND Field

Aspects of the present disclosure generally relate to a method andapparatus for measuring a temperature. Further, aspects of the presentdisclosure relate to non-contact temperature measurement for aprocessing chamber.

Description of the Related Art

During processing associated with fabrication of semiconductor devicesand the like, a number of thermal processing operations are performed ona substrate. Thermal processing generally utilizes temperaturemeasurements for process control. Inaccurate temperature measurementsmay result in poor process results that may adversely influencesemiconductor device performance and/or manufacturing yield.

Optical pyrometry is sometimes used to measure temperature of asubstrate in semiconductor device manufacturing processes. Intensity ofelectromagnetic radiation emitted from the substrate surface is measuredby an optical pyrometry sensor and related to temperature using Planck'sLaw to determine the substrate temperature. In a typical thermalprocessing chamber, optical pyrometers are exposed to electromagneticradiation from many sources, such as lamps and hot surfaces inside thechamber, which masks the electromagnetic radiation emitted by thesubstrate. The interference from electromagnetic noise in the chambercan make it difficult to determine the actual substrate temperature,which may result in erroneous temperature determinations andconsequently poor processing results.

Therefore, there is a need for improved apparatuses and methods forsubstrate temperature measurement.

SUMMARY

Apparatuses and methods for measuring substrate temperature areprovided. In one or more embodiments, an apparatus for estimating atemperature includes a plurality of electromagnetic radiation sourcespositioned to emit electromagnetic radiation toward a reflection plane,and a plurality of electromagnetic radiation detectors, where eachelectromagnetic radiation detector is positioned to sample theelectromagnetic radiation emitted by a corresponding electromagneticradiation source of the plurality of electromagnetic radiation sources.The apparatus also includes a pyrometer positioned to receiveelectromagnetic radiation originating from the plurality ofelectromagnetic radiation sources and reflected from the reflectionplane, and a processor configured to estimate a temperature based on theelectromagnetic radiation received by the pyrometer and by theelectromagnetic radiation detectors.

In other embodiments, a method for estimating a temperature includesemitting, by each of a plurality of electromagnetic radiation sources,electromagnetic radiation toward a substrate, and sampling, by each of aplurality of electromagnetic radiation detectors, the electromagneticradiation emitted by a corresponding electromagnetic radiation source ofthe plurality of electromagnetic radiation sources. The method alsoincludes receiving, by a pyrometer, electromagnetic radiation reflectedfrom the substrate and electromagnetic radiation emitted by thesubstrate; and estimating, using a processor, a temperature of thesubstrate based on the electromagnetic radiation emitted by thesubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 depicts a simplified schematic diagram of a temperaturemeasurement system in accordance with one aspect of the presentdisclosure.

FIGS. 2A, 2B, and 2C illustrate examples of pulse train signals inaccordance with one aspect of the present disclosure.

FIGS. 3A, 3B, and 3C illustrate other examples of pulse train signals inaccordance with one aspect of the present disclosure.

FIG. 4 illustrates a schematic cross-section of a processing chamberhaving the temperature measurement system of FIG. 1 incorporated theretoin accordance with aspects of the present disclosure.

FIG. 5 is a flowchart of an exemplary method for detecting an endpointof the seasoning process in accordance with aspects of the presentdisclosure.

It is contemplated that elements and features of one embodiment may bebeneficially incorporated in other embodiments without furtherrecitation. It is to be noted, however, that the drawings illustrateonly exemplary embodiments of the disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to othereffective embodiments.

DETAILED DESCRIPTION

In one or more embodiments, an apparatus for estimating a temperature isprovided. The apparatus includes a plurality of electromagneticradiation sources positioned to emit electromagnetic radiation toward areflection plane, and a plurality of electromagnetic radiationdetectors. Each electromagnetic radiation detector is positioned tosample the electromagnetic radiation emitted by a correspondingelectromagnetic radiation source of the plurality of electromagneticradiation sources. The apparatus also includes a pyrometer positioned toreceive electromagnetic radiation emitted by plurality ofelectromagnetic radiation sources and reflected from a substratedisposed at a reflection plane and electromagnetic radiation emitted bythe substrate. The apparatus includes a processor configured to estimatea temperature of the substrate based on the electromagnetic radiationemitted by the substrate. Methods of estimating temperature are alsoprovided. FIG. 1 is a simplified schematic diagram of a temperaturemeasurement system 100 in accordance with one aspect of the presentdisclosure. The temperature measurement system 100 includeselectromagnetic radiation sources 102 and 106, electromagnetic radiationdetectors 103 and 108, a pyrometer 110, and a controller 120, positionedadjacent a substrate 101.

The substrate 101 may be a wafer or panel substrate capable of havingmaterial deposited thereon. In one or more examples, the substrate 101may be silicon (doped or undoped), crystalline silicon, silicon oxide,doped or undoped polysilicon, or the like, a germanium substrate, asilicon germanium (SiGe) substrate, a Group III-V compound substrate,such as a gallium arsenide substrate, a silicon carbide (SiC) substrate,a patterned or non-patterned semiconductor-on-insulator (SOI) substrate,a carbon-doped oxide, a silicon nitride, a solar array, solar panel, alight emitting diode (LED) substrate, or any other materials such asmetals, metal alloys, and other conductive materials. In some examples,the substrate 101 may be a substrate holder or a substrate pedestal, achucking plate, or the like. Also, the substrate 101 may include aplurality of layers, such as a semi-insulating material and asemi-conducting material, where the semi-insulating material has ahigher resistivity than the semi-conducting material. The substrate 101is not limited to any particular size or shape. The substrate 101reflects incident electromagnetic radiation having wavelength of about50 μm to about 100 cm according to the electrical resistivity ofsubstrate material near a surface of the substrate 101.

The temperature measurement system 100 also includes signal generators104 and 107. The signal generators 104 and 107 apply time-varying powerto electromagnetic radiation sources 102 and 106, respectively. In oneor more embodiments, each signal generator 104, 107 can generate variouswaveforms with different periodicities, shapes (e.g., sinusoidal pulsesor triangular pulses), patterns, and/or amplitudes. In some cases, thesignal generators 104 and 107 can pulse the power to the electromagneticradiation sources 102 and 106. Use of the signal generators 104 and 107allows for short bursts of electromagnetic radiation to be emitted fromthe electromagnetic radiation sources 102 and 106 to determinereflectivity from the substrate 101.

Electromagnetic radiation source 102 emits electromagnetic radiation L₁having time-varying intensity toward the substrate 101 according to asignal provided by the signal generator 104. Electromagnetic radiationsource 106 emits electromagnetic radiation L₂ having time-varyingintensity toward the substrate 101 according to a signal provided by thesignal generator 107. In one or more embodiments, each of theelectromagnetic radiation sources 102 and 106 can be heat sources (e.g.,heating lamps) which provide thermal energy to the substrate 101 forraising the temperature of the substrate 101.

Electromagnetic radiation detector 103 has a probe head 141 disposedadjacent to the electromagnetic radiation source 102, and detectselectromagnetic radiation L₃ from part of the emission cone 131 ofelectromagnetic radiation source 102. The electromagnetic radiation L₃corresponds to the electromagnetic radiation L₁ that is reflected fromthe substrate 101 and is detected by the pyrometer 110 aselectromagnetic radiation R₁. The probe head 141 of the detector 103 isdisposed in line-of-sight to the emitting element 142 of theelectromagnetic radiation source 102. The electromagnetic radiation inthe emission cone 131 has substantially the same intensity at allemission angles within the emission cone 131. In one or moreembodiments, a probe head 141 of the detector 103 is aligned with aconical surface of the emission cone 131 of the electromagneticradiation source 102. In one or more embodiments, the detector 103 iscoupled to a sampling circuit 105 to determine sampling rates of thedetector 103.

A detector 108 is disposed in line-of-sight to the emitting element 144of the electromagnetic radiation source 106. The electromagneticradiation source 106 includes a light emitting element 144 disposedwithin a reflector 146. The detector 108 includes a probe head 143disposed adjacent to the source 106, and detects electromagneticradiation L₄ from the emission cone 132 of the source 106 correspondingto the electromagnetic radiation L₂. In one or more embodiments, theprobe head 143 of the detector 108 is aligned with a conical surface ofthe emission cone 132 of the electromagnetic radiation source 106. Inone or more embodiments, the detector 108 is coupled to a samplingcircuit 109 to determine sampling rates of the detector 108. Thetemperature measurement system 100 may obtain a higher temperatureresolution at a higher sampling rate.

In one or more embodiments, the detectors 103 and 108 are made ofoptical fibers. In other embodiments, the detectors 103 and 108 includeprobe heads 141, 143 curved at respective angles to be aligned with theradiation beams L₃ and L₄, respectively. In other embodiments, anopening 102 a is formed in a reflector 145 in the electromagneticradiation source 102. The opening 102 a is disposed in a position topass electromagnetic radiation L₅ through the opening 102 a to adetector, such as the detector 103, positioned to receive theelectromagnetic radiation L₅ through the opening 102 a. Although notshown, the electromagnetic radiation source 106 may also include anopening similar to opening 102 a.

The emitting elements 142, 144 of the respective electromagneticradiation sources 102 and 106 emit electromagnetic radiation havinggenerally similar intensity in all directions. Thus, electromagneticradiation L₃ has substantially the same intensity as the correspondingelectromagnetic radiation L₁. Similarly, electromagnetic radiation L₄has substantially the same intensity as electromagnetic radiation L₂. Inoperation, the controller 120 estimates an intensity of theelectromagnetic radiation L₁ from an intensity of the correspondingelectromagnetic radiation L₃. Also, the controller 120 can estimate anintensity of the electromagnetic radiation L₂ from an intensity of thecorresponding electromagnetic radiation L₄.

The pyrometer 110 detects electromagnetic radiation emitted and/orreflected from the substrate 101. The electromagnetic radiation receivedat the pyrometer 110 includes electromagnetic radiation T₁ emitted fromthe substrate 101, and electromagnetic radiation such as L₁ and L₂reflected from the substrate 101. In one or more embodiments, thepyrometer 110 includes an optical narrow-band filter having a bandpassof about 20 nm at a wavelength less than 950 nm, that is, at a photonenergy above the silicon band gap of about 1.1 eV (about 1.1 μm). Thebandpass may be alternately expressed as photon wavelength below theband gap wavelength of the substrate 101. Using pyrometers withnarrow-band functionality reduces noise from other sources in otherspectral bands, thereby improving measurement accuracy.

In some embodiments, the electromagnetic radiation sources 102 and 106may be operated at different wavelengths. In this embodiment, thepyrometer 110 would include detecting elements for the differentwavelengths to separate the radiation from the individualelectromagnetic radiation sources spectrally. In such cases, thetemperature measurement system 100 may determine a reflectivity of thesubstrate 101 while operating the electromagnetic radiation sourcesconcurrently. In such examples, the electromagnetic radiation sources102 and 106 are configured to emit a spectrum of radiation having aplurality of wavelengths from e.g., infrared to ultraviolet. In one ormore embodiments, a Fast Fourier Transform (FFT) analyzer 111 is coupledto the pyrometer 110 to separate reflected radiation received by thepyrometer 110 according to wavelength. In some embodiments, a lock-inamplifier can be coupled to the pyrometer 110 to separate the receivedreflected radiation. In other embodiments, the electromagnetic radiationsources 102 and 106 are operated one at time, either at the samewavelength or at different wavelengths.

The temperature measurement system 100 is connected to a controller 120to control aspects of the temperature measurement system 100 duringprocessing. The controller 120 includes a central processing unit (CPU)121, a memory 122, storage 124, and support circuits 123 for the CPU121. The controller 120 facilitates control of the components of thetemperature measurement system 100, and potentially other components ofan apparatus in which the temperature measurement system 100 is used.The controller 120 may be a general-purpose computer that can be used inan industrial setting for controlling various chambers andsub-processors. The memory 122 stores software (source or object code)that may be executed or invoked to control the overall operations of thetemperature measurement system 100 in manners described herein. Thecontroller 120 manipulates respective operations of controllablecomponents in the temperature measurement system 100. The controller 120may include a power supply for the components of the temperaturemeasurement system 100.

The controller 120 is coupled to the plurality of signal generators 104and 107 and controls signals to be applied to the electromagneticradiation sources 102 and 106 from respective signal generators 104 and107. The controller 105 also receives radiation data from the pyrometer110 and/or circuits corresponding thereto, such as an FFT analyzer (or alock-in amplifier) 111. The controller 105 processes the radiation datareceived by the pyrometer 110 to estimate a temperature of the substrate101 as described below.

In FIG. 1, the electromagnetic radiation sources 102 and 106, thedetectors 103 and 108, and the pyrometer 110 are illustrated to belocated under the substrate 101. However, these components may bedisposed at any convenient location, such as a location above thesubstrate 101, or to one side of the substrate 101 when the substrate101 is oriented vertically. Also, any number of sources 102, 106 anddetectors 103, 108 can be used. Further, more than one pyrometer 110 canbe used to measure temperatures at multiple positions or withindifferent zones of the substrate 101. Multiple sources, detectors, andpyrometers enable improvement in signal-to-noise ratio.

During an operation of monitoring a temperature of the substrate 101,the signal generators 104 and 107 input time-varying signals into theelectromagnetic radiation sources 102 and 106. The electromagneticradiation sources 102 and 106 receive the time-varying signals and emitelectromagnetic radiation L₁ and L₂, respectively, toward the substrate101 based on the input time-varying signals. The radiation L₁illuminates the substrate 101 at incidence angle θ₁, and is partiallyabsorbed, partially transmitted and/or partially reflected. Likewise,the radiation L₂ illuminates the substrate 101 at incidence angle θ₂,and is partially absorbed, partially transmitted and/or partiallyreflected. Reflected radiation R₁ and R₂ proceed towards the pyrometer110.

The detectors 103 and 108 detect radiation L₃ and L₄, which correspondrespectively radiation L₁ and L₂. The radiation L₃ has substantially asame intensity as the corresponding radiation L₁, or the intensity ofthe two radiation components has a defined relationship, so theintensity of the radiation L₃ (measured by the detector 103) can be usedto determine the intensity of the radiation L₁. The radiation L₄ and theradiation L₂ share a similar relationship, facilitating determination ofthe radiation L₂ using the detector 108

The pyrometer 110 detects total intensity of electromagnetic radiation,which is the total intensity of radiation T₁, R₁, and R₂ combined. Theintensity, denoted I_S_(P), of the combined electromagnetic radiationdetected by the pyrometer 110 is thus the intensity I_T₁ of theradiation T₁ plus the intensity I_R₁ of the radiation R₁ plus theintensity I_R₂ of the radiation R₂. The intensity, I_S_(P), of thecombined electromagnetic radiation is thus represented as:I_S _(P) =I_T ₁ +I_R ₁ +I_R ₂  (1)

A reflectivity ρ of the substrate 101 is defined as a ratio of anintensity of a reflection beam (e.g., R₁) to an intensity of an incidentbeam (e.g., L₁). Thus, reflectivity ρ of the substrate 101 isrepresented as:

$\begin{matrix}{\rho = {\frac{\Delta\; R_{2}}{\Delta\; L_{2}} = \frac{\Delta\; R_{1}}{\Delta\; L_{1}}}} & (2)\end{matrix}$

Here, ΔL₁ is the maximum intensity of radiation L₁ (e.g., peaks 201 ofFIG. 2A) minus the minimum intensity of radiation L₁ (e.g., 202 of FIG.2A). Likewise, ΔR₁ is the maximum intensity of reflected radiation R₁minus the minimum intensity of reflected radiation R₁. Similarly, ΔL₂ isthe maximum intensity of radiation L₂ (e.g., 211 of FIG. 2B) minus theminimum intensity of radiation L₂ (e.g., 212 of FIG. 2B). Likewise, ΔR₂is the maximum intensity of reflected radiation R₂ minus the minimumintensity of reflected radiation R₂.

In one or more embodiments, in order to determine the reflectivity ρ,the temperature measurement system 100 can activate only one of theelectromagnetic radiation sources 102, 106 to emit electromagneticradiation and measure reflected radiation. The reflectivity p isdependent on the temperature of the substrate 101, facilitatingdetermination of the temperature of the substrate 101.

The intensity (I_T₁) of the emitted radiation T₁ is represented by thefollowing equation:I_T ₁ =I_S _(P) −I_R ₁ −I_R ₂ =I_S _(P) −ρ×I_L ₁ −ρ×I_L ₂  (3)

As noted above, the electromagnetic radiation L₁ and L₂ each havesubstantially same intensities (I_L₁, I_L₂) of respective correspondingelectromagnetic radiation L₃ and L₄ (e.g., I_L₃, I_L₄) (which is sampledand measured by the electromagnetic radiation detectors 103, 108,respectively). Thus, due to this equality, Equation 3 can be rewrittenas:I_T ₁ =I_S _(P) −I_R ₁ −I_R ₂ =I_S _(P) −ρ×I_L ₃ −ρ×I_L ₄  (4)

The absolute temperature T of the sample is calculated by applyingPlanck's Law, which holds that the emitted radiation T₁=B_(v)(v,T),where spectral radiance of frequency v from a body at absolutetemperature T is given by:

$\begin{matrix}{{B_{v}\left( {v,T} \right)} = {\frac{2{hv}^{3}}{c^{2}}\frac{1}{e^{\frac{hv}{k_{B}T}} - 1}}} & (5)\end{matrix}$Here, k_(B) is Boltzmann's constant, h is Planck's constant, and c isthe speed of light in the medium, whether material or vacuum, and T isan absolute temperature of the substrate 101. Adherence to Planck's Lawis generally mediated by an object's emissivity, which is defined as theratio of actual thermal radiation output to theoretical output accordingto Planck's Law. Thus, Planck's Law can be used to estimate temperatureof an object, such as the substrate 101.

The above series of equations describe how to estimate a temperature ofthe substrate 101 based on two radiation samples. However, theseequations can be extended to any embodiment where a pyrometer receivesan arbitrary number of radiation samples as discussed further below.

FIGS. 2A, 2B, and 2C illustrate examples of pulse train signals inaccordance with one aspect of the present disclosure. Examples oftime-varying power signals are illustrated in FIGS. 2A and 2B. Thetime-varying power signals (e.g., pulsed signals) may be used to gauge areflectivity of a substrate, such as the substrate 101 shown in FIG. 1,during a calibration process performed with each new substrate. When anew substrate is introduced to an apparatus having a temperaturemeasurement system therein, such the temperature measurement systemdescribed in connection with FIG. 1, each electromagnetic radiationsource is pulsed a plurality of times, for example, 10 times, todetermine the reflectivity of the substrate. In one or more embodiments,the temperature measurement system may rotate the substrate whilepulsing the electromagnetic radiation sources, in case the reflectivityvaries across a surface of the substrate. In other embodiments, thetemperature measurement system may synchronize pulsing with therotation, so the system double-samples the reflectivity using thedifferent detectors 103 and 108.

FIG. 2A illustrates a signal 200 to be applied to the electromagneticradiation source 102, which in turn emits electromagnetic radiation L₁having time-varying intensity according to the signal 200. FIG. 2Billustrates a signal 210 to be applied to the electromagnetic radiationsource 106, which in turn emits electromagnetic radiation L₂ havingtime-varying intensity according to the signal 210. The signal 200 is atime-varying voltage that has a peak 201 with a peak voltage V_(L1) in aperiod time of t₁. The signal 210 is a time-varying voltage, with twopeaks 211, each having a peak voltage V_(L2), in a period time of t₂. Inthis embodiment, the peaks 201 and 211 do not overlap in time. FIG. 2Cillustrates an exemplary signal 220 received by the pyrometer 110 whenthe electromagnetic radiation sources 102 and 106 are operated accordingto the signals 200 and 210, respectively. The pyrometer 110 receivesreflected radiation R₁ and R₂, originating from the respectiveelectromagnetic radiation sources 102 and 106, and emitted radiation T₁,which originates from the substrate 101 due to thermal energy of thesubstrate 101. The received signal 220 has three pulses, a first pulse221 corresponding to the peak 201 of the signal 200 and second and thirdpulses 222 and 223 corresponding to the peaks 211 of the signal 210.

Different examples of time-varying power signals are illustrated inFIGS. 3A and 3B. FIG. 3A illustrates a signal 300 to be applied to theelectromagnetic radiation source 102, and FIG. 3B illustrates a signal310 to be supplied to the electromagnetic radiation source 106. Thesignal 300 is a time-varying voltage that has a peak 301 with a peakvoltage V_(L1) in a period time of t₁. The signal 310 is a time-varyingvoltage that has two peaks 311, 312, each with peak voltage V_(L2) in aperiod time of t₂. Here, one peak 301 overlaps in time with a peak 311.

FIG. 3C illustrates an exemplary signal 320 received by the pyrometer110 when the electromagnetic radiation sources 102 and 106 are operatedaccording to the signals 300 and 310, respectively. The received signal320 has two pulses, a first pulse 321 corresponding to the overlappedpeaks 301 and 311, and a second pulse 322 corresponding to the peak 312.The first pulse 321 is produced by reflected electromagnetic radiationfrom both electromagnetic radiation sources 102 and 106 being receivedconcurrently by the pyrometer 110.

Referring again to FIG. 1, electromagnetic radiation sources 102 and 106emit electromagnetic radiation at all azimuthal angles in respectiveemission cones 131 and 132 toward the substrate 101. The electromagneticradiation illuminates the substrate 101, and is partially absorbed,partially transmitted, and partially reflected in correspondingreflection cones in varying amounts at different wavelengths.Electromagnetic radiation reflected in a certain range of reflectionangles proceeds toward, and may be detected by, the pyrometer 110. Forexample, using a ray-tracing approach for clarity, radiation L₁ and L₂emitted in corresponding emission cones 131 and 132 from electromagneticradiation sources 102 and 106 are incident at the substrate 101 withincidence angles θ₁ and θ₂, respectively, and partially reflected at thesubstrate 101. Reflected radiation R₁ and R₂ proceeds in a reflectionarea 133 toward and is detected by the pyrometer 110 as illustrated inFIG. 1. The reflection area 133 sampled by the pyrometer 110 contains aportion, defined by the azimuth viewed by the pyrometer 110, of a bandof radiation reflected by the substrate 101 from each emission cone 131and 132. When the incidence angles θ₁ and θ₂ are within a particularrange, the reflected radiation is detected by the pyrometer 110 over theazimuth viewed by the pyrometer 110.

FIG. 4 illustrates a schematic cross-section of a processing chamber 400incorporating the temperature measurement system 100 of FIG. 1. Theprocessing chamber 400 features an enclosure 402, a substrate support404 disposed in the enclosure 402, a processing module 403 coupled tothe enclosure 402, a plurality of electromagnetic radiation sources 405(405-1, 405-2, 405-3, 405-4, 405-5, and 405-6) and signal generators 407(407-1, 407-2, 407-3, 407-4, 407-5, and 407-6) coupled to the pluralitysources 405, a plurality of detectors 406 (406-1, 406-2, 406-3, 406-4,406-5, and 406-6), and a pyrometer 408.

The processing module 403 includes one or more conduits 411 (two areshown) for introducing materials into the enclosure 402. The conduits411 may be used for introducing gases or liquids, and may be straight,as shown in FIG. 4, or tortuous to any desired degree. Two conduits 411are shown in FIG. 4, but any number may be used. For example, theprocessing module 403 may include a showerhead, which may have multiplezones or pathways. The processing module 403 may be coupled to anydesired delivery apparatus, such as gas boxes, evaporators, ampoules,and the like through appropriate conduits.

The substrate support 404 is heated by heating lamps embedded in thesubstrate support 404. The substrate support 404 may also beelectrified, for example using bias elements, to provide electrostaticimmobilization of a substrate 401 on the substrate support 404. Arotational drive (not shown) may be coupled to the substrate support 404to provide rotary motion during processing, between processing cycles,or both. In embodiments wherein the substrate 401 is rotated duringprocessing, the substrate 401 may be probed at selected intervals tomonitor the temperature of different locations on the substrate 401 sothat temperature uniformity may be controlled.

Each signal generator 407-1 to 407-6 is coupled to a respectiveelectromagnetic radiation source 405. The signal generators 407-1 to407-6 each generate time-varying signals and apply the time-varyingsignals to the respective electromagnetic radiation source 405. Theelectromagnetic radiation sources 405-1 to 405-6 emit electromagneticradiation L₁ through L₆ toward the substrate 401. The plurality ofelectromagnetic radiation sources 405-1 to 405-6 can be heat sources forproviding thermal energy to the substrate 401.

Each detector 406-1 to 406-6 is disposed adjacent to a respectiveelectromagnetic radiation source 405-1 to 405-6 to detectelectromagnetic radiation L_(1a)-L_(6a) corresponding to electromagneticradiation L₁-L₆, which are partially reflected at the substrate 401 andare received by the pyrometer 408. A portion of each electromagneticradiation detector 406-1 to 406-6 is positioned in line-of-sight to theemitting element of a respective electromagnetic radiation source 405-1to 405-6. The electromagnetic radiation detectors 406-1 to 406-6 includesupport circuits to sample the radiation beams L_(1a)-L_(6a) atrespective sampling rates.

The processing chamber 400 can include any number of sources 405, eachwith a corresponding signal generator 407 and electromagnetic radiationdetector 406.

The pyrometer 408 detects electromagnetic radiation propagating towardthe pyrometer 408 from the substrate 401. The radiation detected by thepyrometer 408 includes radiation T₁ emitted from the substrate 401 andthe reflected radiation R₁-R₆.

In operation, the processing chamber 400 estimates a temperature of thesubstrate 401 in a manner similar to that described above with respectto FIG. 1. Here, the processing chamber 400 includes six (6)electromagnetic radiation sources 405-1 to 405-6 and detector 406-1 to406-6 s, but any number of sources and detectors can be used. In suchembodiments, the pyrometer 408 will return the intensity of radiationI_S_(P) sourced from any number of electromagnetic radiation sources,reflected from the substrate 401, and the emitted electromagneticradiation T₁ as follows:I_S _(P) =I_T ₁+Σ_(i=1) ^(i=n) I_R _(i)  (6)

Based on the definition of the reflectivity p, which can be determinedas described above in connection with FIGS. 2A-3C, Equation 6 can berewritten as:I_T ₁ =I_S _(P)−Σ_(i=1) ^(i=n) ρI_L _(i)  (7)

Each electromagnetic radiation L₁, L₂, L₃, . . . L_(n) has substantiallythe same intensity as the corresponding electromagnetic radiationL_(1a), L_(2a), L_(3a), . . . L_(na), which are sampled by theelectromagnetic radiation detectors 406. Thus, Equation 7 can berewritten as:I_T ₁ =I_S _(P)−Σ_(i=1) ^(i=n) ρI_L _(ia)  (8)Consequently, the intensity I_T₁ of the emitted electromagneticradiation is calculated by subtracting the intensity Σ_(i=1)^(i=n)ρI_L_(ia) of the reflected radiation, based on the determinedreflectivity p and the incident electromagnetic radiation I_L_(ia)detected by the detectors 406, from the intensity I_S_(P) of the totalradiation returned by the pyrometer 408. The temperature of thesubstrate 401 is then estimated by applying Planck's Law to theintensity I_T₁ of the emitted electromagnetic radiation T₁, as describedin association with FIG. 1.

The electromagnetic radiation sources, detectors, and pyrometer areshown in FIG. 4 installed below the substrate 401. However, thesecomponents may be disposed at any convenient location in the processingchamber 400, such as a location above the substrate 401.

The processing chamber 400 may be a chemical vapor deposition (CVD)chamber, such as a plasma enhanced CVD chamber, a high-density plasmaCVD chamber, a low pressure CVD chamber, a reduced pressure CVD chamber,or an atmospheric pressure CVD chamber. In other embodiments, theprocessing chamber 400 may also be a PVD chamber, an etch chamber(thermal or plasma), an epitaxy chamber, an anneal chamber, or any otherprocessing chamber in which temperature monitoring might be useful.Examples of the processing chamber 400 can include CVD chambers such asAKT® PECVD chambers, PRODUCER™ chambers, and PRECISION 5000® chamberscommercially available from Applied Materials Inc., Santa Clara, Calif.

The controller 420 may be substantially identical to the controller ofFIG. 1. The controller 420 may be coupled to the pyrometer 408 andrelevant circuits thereof to monitor data received by the pyrometer 408and process the data to estimate a temperature of the substrate 401.

In one or more embodiments, the processing chamber 400 can include aplurality of pyrometers 408 to detect temperatures at multiple positionsof the substrate 401. By using the temperature indications from theplurality of pyrometers 408, temperature non-uniformity of the substrate401 can be detected, and the temperature uniformity thereof can beimproved.

In other embodiments, a plurality of substrates may be disposed on thesubstrate support 404 to be concurrently processed in the processingchamber 400, and a plurality of pyrometers can be provided, with one ormore pyrometers corresponding to each substrate.

FIG. 5 is a flowchart 500 for an exemplary method of estimatingsubstrate temperature in accordance with aspects of the presentdisclosure.

In operation 502, a signal generator is used to generate pulsed signalsof time-varying power to an electromagnetic radiation source. The signalgenerator can generate various waveforms with different periodicities,pulse shapes (e.g., sinusoidal pulses or triangular pulses), pulsepatterns and/or amplitudes. More than one electromagnetic radiationsource can be used, with each electromagnetic radiation source includinga respective signal generator.

In operation 504, the electromagnetic radiation source emitselectromagnetic radiation toward a substrate according to the signalfrom the signal generator. In the event multiple electromagneticradiation sources are used, each source emits according to the signalfrom the corresponding signal generator.

In operation 506, a detector detects electromagnetic radiation,including the radiation emitted by the electromagnetic radiation source.In one or more embodiments, a probe head of each detector is disposed inline-of-sight to an emitting element of a corresponding electromagneticradiation source. The emitted electromagnetic radiation has asubstantially constant intensity at all angles. In one or moreembodiments, a probe head of the detector can be aligned to a conicalsurface of the emission cone of the electromagnetic radiation source. Inthe event multiple electromagnetic radiation sources are used, eachsource has a corresponding detector.

In operation 508, a pyrometer detects the intensity of electromagneticradiation emitted and/or reflected from the substrate. Theelectromagnetic radiation received at the pyrometer includes thermalelectromagnetic radiation emitted from the substrate, andelectromagnetic radiation reflected from the substrate.

In operation 510, the controller determines the intensity of the emittedelectromagnetic radiation (T₁ in FIG. 1) by subtracting a sum of sampledelectromagnetic radiation intensities from the total intensity of theelectromagnetic radiation received by the pyrometer to obtain theemitted intensity. The controller further estimates a temperature T ofthe substrate by applying the Planck's law to the determined emittedelectromagnetic radiation intensity as described above.

Embodiments of the present disclosure further relate to any one or moreof the following paragraphs:

1. An apparatus for estimating a temperature, comprising: a plurality ofelectromagnetic radiation sources positioned to emit electromagneticradiation toward a reflection plane; a plurality of electromagneticradiation detectors, each electromagnetic radiation detector positionedto sample the electromagnetic radiation emitted by a correspondingelectromagnetic radiation source of the plurality of electromagneticradiation sources; a pyrometer positioned to receive electromagneticradiation originating from the plurality of electromagnetic radiationsources and reflected from the reflection plane; and a processorconfigured to estimate a temperature based on the electromagneticradiation received by the pyrometer and by the electromagnetic radiationdetectors.

2. An apparatus for estimating a temperature, comprising: a plurality ofelectromagnetic radiation sources positioned to emit electromagneticradiation toward a reflection plane, wherein each electromagneticradiation source is configured to emit electromagnetic radiation in anemission cone; a plurality of electromagnetic radiation detectors, eachelectromagnetic radiation detector positioned to sample theelectromagnetic radiation emitted by a corresponding electromagneticradiation source of the plurality of electromagnetic radiation sources;a pyrometer positioned to receive electromagnetic radiation originatingfrom the plurality of electromagnetic radiation sources and reflectedfrom the reflection plane; and a processor configured to estimate atemperature based on the electromagnetic radiation received by thepyrometer and by the electromagnetic radiation detectors.

3. A method for estimating a temperature, the method comprising:emitting, by each of a plurality of electromagnetic radiation sources,electromagnetic radiation toward a substrate; sampling, by each of aplurality of electromagnetic radiation detectors, the electromagneticradiation emitted by a corresponding electromagnetic radiation source ofthe plurality of electromagnetic radiation sources; receiving, by apyrometer, electromagnetic radiation reflected from the substrate andelectromagnetic radiation emitted by the substrate; and estimating,using a processor, a temperature of the substrate based on theelectromagnetic radiation emitted by the substrate.

4. The apparatus or the method according to any one of paragraphs 1-3,wherein each electromagnetic radiation detector includes a probe headdisposed in line-of-sight to an emitting element of the correspondingelectromagnetic radiation source.

5. The apparatus or the method according to paragraph 4, wherein eachelectromagnetic radiation source is configured to emit electromagneticradiation in an emission cone toward the reflection plane, and a portionof the electromagnetic radiation in the emission cone at a first angleis reflected from the reflection plane and then is received by thepyrometer.

6. The apparatus or the method according to paragraph 5, wherein a probehead of each electromagnetic radiation detector is curved to be alignedto a conical surface of the emission cone, and is configured to samplethe electromagnetic radiation in the emission cone at a second angle.

7. The apparatus or the method according to paragraph 6, wherein the oneportion of electromagnetic radiation in the emission cone at the firstangle has a substantially same intensity as another portion ofelectromagnetic radiation in the emission cone at the second angle.

8. The apparatus or the method according to any one of paragraphs 1-7,wherein the processor is configured to receive an intensity ofelectromagnetic radiation received by the pyrometer and an intensity ofelectromagnetic radiation sampled by the electromagnetic radiationdetectors, determine an intensity of reflected radiation from thereflection plane from the intensity of electromagnetic radiation sampledby the electromagnetic radiation detectors, and subtract the intensityof reflected radiation from the electromagnetic radiation received bythe pyrometer to estimate the temperature.

9. The apparatus or the method according to paragraph 8, wherein theintensity of reflected radiation from the reflection plane is determinedby applying a known reflectivity at the reflection plane to theintensity of electromagnetic radiation sampled by the electromagneticradiation detectors.

10. The apparatus or the method according to paragraph 9, wherein thereflectivity is determined by: calculating a first quantity bysubtracting a minimum intensity of electromagnetic radiation sampled bythe electromagnetic radiation detector from a maximum intensity ofelectromagnetic radiation sampled by the electromagnetic radiationdetector; calculating a second quantity by subtracting a minimumintensity of electromagnetic radiation detected by the pyrometer from amaximum intensity of electromagnetic radiation detected by thepyrometer; and calculating a ratio of the first quantity to the secondquantity.

11. The apparatus or the method according to any one of paragraphs 1-10,wherein the temperature is estimated by applying Planck's Law to adifference between an intensity of electromagnetic radiation received bythe pyrometer and an intensity of electromagnetic radiation reflectedfrom the reflection plane.

12. The apparatus or the method according to paragraph 11, wherein eachelectromagnetic radiation detector includes a probe head disposed inline-of-sight to an emitting element of the correspondingelectromagnetic radiation source.

13. The apparatus or the method according to paragraph 12, wherein eachelectromagnetic radiation source emits electromagnetic radiation in anemission cone toward the substrate, and a portion of the electromagneticradiation in the emission cone at a first angle is reflected from thereflection plane and then is received by the pyrometer.

14. The apparatus or the method according to paragraph 13, wherein aprobe head of each electromagnetic radiation detector is curved to bealigned to a conical surface of the emission cone, and is configured tosubstrate the electromagnetic radiation in the emission cone at a secondangle.

15. The apparatus or the method according to paragraph 14, whereinelectromagnetic radiation in the emission cone at the first angle hassubstantially the same intensity as electromagnetic radiation in theemission cone at the second angle.

16. The apparatus or the method according to paragraph 15, furthercomprising determining electromagnetic radiation emitted by thesubstrate by subtracting the electromagnetic radiation reflected fromthe substrate from the electromagnetic radiation received by thepyrometer.

17. The apparatus or the method according to paragraph 16, furthercomprising calculating the intensity of electromagnetic radiationemitted by the substrate by multiplying the intensity of electromagneticradiation sampled by each electromagnetic radiation source by a knownreflectivity of the substrate, summing the result, and subtracting thesum from the intensity of electromagnetic radiation received by thepyrometer.

18. The apparatus or the method according to paragraph 17, wherein thereflectivity of the substrate is a ratio of an intensity of reflectedelectromagnetic radiation to an intensity of incident electromagneticradiation.

19. The apparatus or the method according to paragraph 17, wherein thereflectivity of the substrate is calculated by dividing a maximumintensity minus a minimum intensity of electromagnetic radiation emittedby an electromagnetic radiation source by a maximum intensity minus aminimum intensity of electromagnetic radiation emitted by theelectromagnetic radiation source and reflected from the reflectionplane.

20. The apparatus or the method according to any one of paragraphs 1-19,further comprising estimating a temperature of the substrate by applyingPlanck's Law to the electromagnetic radiation emitted by the substrate.

The preceding description is provided to enable any person skilled inthe art to practice the various embodiments described herein. Variousmodifications to these embodiments will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other embodiments. For example, changes may be made in thefunction and arrangement of elements discussed without departing fromthe scope of the disclosure. Various examples may omit, substitute, oradd various procedures or components as appropriate. Also, featuresdescribed with respect to some examples may be combined in some otherexamples. For example, an apparatus may be implemented or a method maybe practiced using any number of the aspects set forth herein. Inaddition, the scope of the disclosure is intended to cover such anapparatus or method that is practiced using other structure,functionality, or structure and functionality in addition to, or otherthan, the various aspects of the disclosure set forth herein. It shouldbe understood that any aspect of the disclosure disclosed herein may beembodied by one or more elements of a claim.

As used herein, the word “exemplary” means “serving as an example,instance, or illustration.” Any aspect described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother aspects.

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

The methods disclosed herein include one or more operations or actionsfor achieving the methods. The method operations and/or actions may beinterchanged with one another without departing from the scope of theclaims or the disclosure. In other words, unless a specific order ofoperations or actions is specified, the order and/or use of specificoperations and/or actions may be modified without departing from thescope of the claims.

The following claims are not intended to be limited to the embodimentsshown herein, but are to be accorded the full scope consistent with thelanguage of the claims. Within a claim, reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. No claim element is tobe construed under the provisions of 35 U.S.C. § 112(f) unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.” All structural and functional equivalents to the elements of thevarious aspects described throughout this disclosure that are known orlater come to be known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

The invention claimed is:
 1. A method for estimating a temperature, themethod comprising: emitting, by each of a plurality of electromagneticradiation sources, electromagnetic radiation toward a substrate;sampling, by each of a plurality of electromagnetic radiation detectors,the electromagnetic radiation emitted by a corresponding electromagneticradiation source of the plurality of electromagnetic radiation sources;receiving, by a pyrometer, electromagnetic radiation reflected from thesubstrate and electromagnetic radiation emitted by the substrate; andestimating, using a processor, a temperature of the substrate based onthe electromagnetic radiation emitted by the substrate.
 2. The method ofclaim 1, further comprising estimating the temperature of the substrateby applying Planck's Law to the electromagnetic radiation emitted by thesubstrate.
 3. The method of claim 1, wherein each electromagneticradiation detector includes a probe head disposed in a line-of-sight toan emitting element of the corresponding electromagnetic radiationsource.
 4. The method of claim 3, wherein each electromagnetic radiationsource emits electromagnetic radiation in an emission cone toward thesubstrate, and a portion of the electromagnetic radiation in theemission cone at a first angle is reflected from a reflection plane andthen is received by the pyrometer.
 5. The method of claim 4, wherein theprobe head of each electromagnetic radiation detector is curved to bealigned to a conical surface of the emission cone, and is configured toemit the electromagnetic radiation in the emission cone at a secondangle.
 6. The method of claim 5, wherein electromagnetic radiation inthe emission cone at the first angle has substantially the sameintensity as electromagnetic radiation in the emission cone at thesecond angle.
 7. The method of claim 6, further comprising determiningelectromagnetic radiation emitted by the substrate by subtracting theelectromagnetic radiation reflected from the substrate from theelectromagnetic radiation received by the pyrometer.
 8. The method ofclaim 7, further comprising; each of the electromagnetic radiationdetectors sampling the electromagnetic radiation emitted by acorresponding electromagnetic radiation source of the plurality ofelectromagnetic radiation sources; and calculating the intensity ofelectromagnetic radiation emitted by the substrate by multiplying theintensity of electromagnetic radiation sampled by each electromagneticradiation detector by a known reflectivity of the substrate, summing theresult, and subtracting the sum from the intensity of electromagneticradiation received by the pyrometer.
 9. The method of claim 8, whereinthe reflectivity of the substrate is a ratio of an intensity ofreflected electromagnetic radiation to an intensity of incidentelectromagnetic radiation.
 10. The method of claim 8, wherein thereflectivity of the substrate is calculated by dividing a maximumintensity minus a minimum intensity of electromagnetic radiation emittedby an electromagnetic radiation source by a maximum intensity minus aminimum intensity of electromagnetic radiation emitted by theelectromagnetic radiation source and reflected from the reflectionplane.